Livestock fence with plastic tube over the top wire, SR 260, west of Kohl's Ranch, Arizona, USA. The PVC tube makes the fence and especially the top wire more visible to wildlife (e.g. elk and deer), and the animals are less likely to injure themselves or get entangled when they cross the fence. This particular livestock fence is in front of a wildlife underpass designed for elk and deer. Naturally this is where it is desirable to have elk and deer cross livestock fences easily.